The traditional teleconference facility is generally a shared, extremely high cost facility whose use is tightly scheduled. Such teleconference facilities put extreme limitations on the normal human protocols for interaction. Most conventional teleconference facilities offer some version of an NTSC (home television like) video display on relatively small sized monitors. When the number of teleconference participants at a sending end of a teleconference is larger than one, the image of each participant occupies a small portion of an already small viewing area at the receiving end. As a result, it becomes difficult for viewers at the receiving end of such an image to pick up non-verbal queues from the speaker's face and body. Indeed, in many cases, it is often difficult to discern who of the many participants is actually speaking.
In contrast to the conventional teleconference facility described above, Judd et al, U.S. Pat. No. 4,890,314 issued Dec. 26, 1989, describes a teleconferencing system which is especially suited for casual communication between groups of participants at either end of a telecommunications link. The contents of U.S. Pat. No. 4,890,314 are incorporated herein by reference. The teleconferencing system of the above-identified patent provides video and audio communications for the groups of participants. Illustratively, common conference rooms and lounges may be adapted for use as teleconferencing stations. In such a room, one wall may be adapted as a video display for displaying a high resolution video image. The display allows participants at the other end of a teleconference to appear almost life-sized. The high resolution display has a wider aspect ratio than standard NTSC video to match the generally wider, than taller, view of side by side seated conference participants.
One candidate for providing such a high resolution, wide aspect ratio, video image is High Definition Television (HDTV) equipment. Unfortunately, the high cost and high transmission bandwidth (approximately 1 Gigabit/sec for digital transmission and 30 Mhz for analog transmission) and the requirements for high lighting levels at the conference sites make presently available HDTV equipment unsuitable for casual teleconferencing applications.
The above-mentioned U.S. Pat. No. 4,890,314 discloses an alternative approach for forming a high resolution video image wherein two or more cameras are utilized to produce a signal with more resolution (i.e. more pixels) than a single camera. In such a system each camera has a projector or other display device associated therewith to produce a sub-image which forms a portion of the high resolution video image. When the cameras are arranged to have contiguous fields of view, the sub-images provided by the various cameras may be positioned adjacent one another to form a single high resolution image. Techniques for arranging the cameras so that they have non-overlapping and/or contiguous fields of view are described in the above-mentioned U.S. Pat. No. 4,890,314. In general, the cameras cannot simply be placed next to each other as such an arrangement results in a complex situation wherein some locations are in the field of view of both cameras and some locations are in the field of view of neither cameras. To overcome this problem, the cameras are placed at spaced apart positions and a mirror system is illustratively utilized to insure that the cameras have contiguous fields of view.
When such a technique for forming a high resolution image is utilized, a station for use in a teleconferencing system comprises first and second video display devices for receiving first and second video signals generated by first and second imaging devices (e.g. video cameras) having first and second spaced apart positions at a location remote from the teleconferencing station and substantially contiguous fields of view. The first and second display devices display first and second low resolution sub-images, respectively, in response to the first and second video signals. The first and second low resolution sub-images are displayed in adjoining positions so that they merge contiguously to form a single high resolution video image. The teleconferencing station also includes third and fourth low resolution video imaging devices having third and fourth spaced apart positions at the teleconferencing station, for generating third and fourth video signals corresponding to third and fourth low resolution video sub-images. The third and fourth video signals are transmitted to the remote location for formation of a second high resolution video image at the remote location.
An important aspect of the type of teleconferencing station described above is the simplicity of its user interface. Generally, there are no controls for the user to adjust. Illustratively, a first teleconferencing station is continuously connected to a particular second teleconferencing station at a remote location so that users are free to interact casually and spontaneously with whomever is at the other end.
As previously indicated above, the above described teleconferencing station may be incorporated as part of a conference room. The conference room generally includes a wider than taller high resolution video display, inconspicuous cameras, a seating area, and a conference table. Illustratively, each teleconferencing station in the teleconferencing system is arranged so that a group of participants at each station can sit behind a local conference table and have a feeling of "being together" at a conference with another group of participants sitting behind their own conference table at their own teleconferencing station. The basic teleconferencing station described above provides groups of users with the ability to see and talk to each other. Often, however, users have the desire (especially in a business setting) to show each other information formed on copy material. The information may be contained on a transparent copy material such as a transparency or slide. Alternatively, the information may be written or otherwise impressed on a translucent copy material such as a single piece of paper. Alternatively, the information may be contained in an opaque copy material such as a page of a hardbound book.
It is an object of the present invention to provide teleconference participants with the ability to exchange information contained on such copy material.
Devices are available (e.g. the VIDEOGRAPHE device of Thomson Video) which enable copy material to be displayed on a video display. However, such prior art devices have a number of shortcomings. The prior art devices do not reconfigure themselves automatically to display information contained in a transparent, translucent, or opaque copy material without the need for user intervention, as would be highly desirable in the type of informal teleconferencing setting described above. Furthermore, the prior art devices provide no mechanism by which such devices can be used with a teleconferencing system, wherein each teleconferencing station includes a high resolution video display which forms a high resolution video image by combining a plurality of low resolution video sub-images. In particular, the prior art devices do not provide a signal which is asserted in the presence of copy material to activate external equipment so that a video image of the copy material can be combined with other video images.
Accordingly, it is an object of the invention to provide a video imaging device which enables teleconference participants to exchange information contained in copy material, wherein the copy material is transparent, translucent, or opaque.
It is a further object of the invention to provide a video imaging device for displaying information contained in copy material, which imaging device automatically reconfigures itself depending on whether the copy material is transparent, translucent, or opaque.
It is also an object of the invention to provide a video imaging device for displaying information contained in copy material on a video display of a teleconferencing station, which video display forms a high resolution image by combining a plurality of low resolution video sub-images.